Virological survey of rhesus monkeys in China

A virological survey of rhesus monkeys captured in China for 13 viruses and/or antibodies was performed. Antigens used were SFV, SF40, HSV-1, Sa11, measles, vaccinia, epidemic or simian hemorrhagic fever, Langat, Kunming, poliomyelitis, HIV, SV41 and rubella. Monkeys were from Sichuan, Hunan, Guizhou, Yunnan and Guangxi provinces. Antibody was detected to all the listed viruses except HIV, SV41 and rubella. Both SFV and SV40 were recovered from monkeys, but H. simiae, LCM and coxsackieviruses were not.     

兔的一种新病毒：Ⅱ.一株兔出血症...

In this paper a strain of Rabbit Hemorrhagic Disease Virus (RHDV) was isolated and purified from the diseased rabbit livers with a method of using chloroform, two-phase of polyethylene-glycol-dextran sulfate sodium and sucrose density gradient centrifugation. Purified virus was nonenveloped, icosahedeal symmetry with a triangulation number of 3, and 33-37 nm in diameter. The capsid was composed of 32 capsomeres with central holes in an outer diameter of about 9nm. Two types of viral particles having different sedimentation coefficient, 130s and 166s could be identified after sucrose density gradient centrifugation. Probably no less than four virion proteins with molecular weight of 66.4, 65.0, 63.5, 41.0 x 10(3) dalton were detected by SDS-polyacrylamide gel electrophoresis. Viral nucleic acid was extracted from purified virus by using SDS-proteinase K-phenol. Tests with diphenylamine, formaldehyde, and staining with acridine orange as well as the curves of thermal denaturation showed that this kind of virus had a single-stranded DNA. The molecular weight of the ssDNA was approx 2.1 x 10(6) dalton as determined by electron microscopy. Data indicate that the RHDV may like the parvovirus of the family Parvoviridae.     

Isolation and characterization of two opioid peptides from a bovine hemoglobin peptic hydrolysate.

Two opioid peptides were isolated from a bovine hemoglobin hydrolysate, by use of gel permeation (GP) and reverse phase (RP) high performance liquid chromatography (HPLC). Their primary structure and accurate molecular weights, determined by amino acid analysis and fast atom bombardment (FAB) mass spectrometry, were identical to fragments 31-40 (LVV-hemorphin-7) and 32-40 (VV-hemorphin 7) of the beta-chain of bovine hemoglobin. The same fragments occur in human hemoglobin in positions 32-41 and 33-41 of the beta-chain, respectively. The opioid potency of these peptides, exhibited by use of electrically stimulated muscle of isolated guinea-pig ileum (GPI), were significant and comparable with some others previously described. In addition, the location of the two opioid peptides, VV-hemorphin-7 and LVV-hemorphin-7, revealed the existence of a "strategic zone" both in the bovine and human beta-chains of hemoglobin.     

Fractal analysis of protein chain conformation

This paper presents a simple practical method for characterizing conformation of protein chains. A single number Df, as the fractal dimension, is assigned to each chain. Df = Ln(N)/Ln(N.d/L), where N is the number of the amino acid residues in the chain, L and d are the total length and the planar diameter of the chain, respectively. In general, 1 less than Df less than or equal to 2, which is related to the shape of the protein chain. These values are different from those of Stapleton's group, but in agreement with computer simulations.     

越桔亚科植物化学成分研究进展

本文综述了近年来越桔亚科植物的研究进展。分别介绍了越桔属,红梅苔子属等化学成分研究的概况。     

FliG and FliM distribution in the Salmonella typhimurium cell and flagellar basal bodies.

Salmonella typhimurium FliG and FliM are two of three proteins known to be necessary for flagellar morphogenesis as well as energization and switching of flagellar rotation. We have determined FliG and FliM levels in cellular fractions and in extended flagellar basal bodies, using antibodies raised against the purified proteins. Both proteins were found predominantly in the detergent-solubilized particulate fraction containing flagellar structures. Basal flagellar fragments could be separated from partially constructed basal bodies by gel filtration chromatography. FliG and FliM were present in an approximately equimolar ration in all gel-filtered fractions. FliG and FliM copy numbers, estimated relative to that of the hook protein from the early fractions containing long, basal, flagellar fragments, were (means +/- standard errors) 41 +/- 10 and 37 +/- 13 per flagellum, respectively. Extended structures were present in the earliest identifiable basal bodies. Immunoelectron microscopy and immunoblot gel analysis suggested that the FliG and, to a less certain degree, the FliM contents of these structures were the same as those for the complete basal bodies. These facts are consistent with the postulate that FliG and FliM affect flagellar morphogenesis as part of the extended basal structure, formation of which is necessary for assembly of more-distal components of the flagellum. The determined stoichiometries will provide important constraints to modelling energization and switching of flagellar rotation.     

An 18-base-pair sequence is sufficient for termination of rolling-circle replication of plasmid pT181.

pT181 and related plasmids of gram-positive bacteria replicate by a rolling-circle mechanism. The replication initiator protein of pT181, RepC, has origin-specific nicking-closing activities. Replication of the plasmid pT181 leading strand initiates by covalent extension of the RepC-generated nick, and the origin of replication contains signals for both initiation and termination of DNA replication. We have investigated the sequence requirements for the initiation and termination steps by using plasmids containing two pT181 origins. In vitro replication experiments showed that 18- and 24-bp synthetic oligonucleotides containing the RepC nick site were active in the termination of replication. However, initiation of replication required a larger region which also includes the RepC binding site. Plasmids containing the 18- and 24-bp region were also found to be nicked by the RepC protein. Our results demonstrate that sequence requirements for initiation and termination of pT181 replication overlap, but while the RepC binding site is required for initiation, it is dispensable for termination.     

Effects of anti-peptide antibodies against the second extracellular loop of human M2 muscarinic acetylcholine receptors on transmembrane potentials and currents in guinea pig ventricular myocytes

The effects of anti-peptide antibodies against the second extracellular loop of human M2 muscarinic receptor on transmembrane potentials and currents in guinea pig single ventricular cells were analyzed using whole-cell patch clamp technique. These effects were compared with those of the muscarinic receptor agonists carbachol and acetylcholine. The antibodies shortened the action potential duration in a dose-dependent manner. By using a ramp or step rectangular pulse protocol, it was found that the antibodies increased the outward K⁺ current and decreased the inward basal I Ca significantly. The reversal potential of both carbachol-and antibody-induced extra currents were close to –80 mV, being in proximity to the calculated E_k of –90 mV. A -adrenergic receptor agonist, isoprenaline, prolonged the action potential and increased the overshoot which could be inhibited by both antibody and carbachol. Isoprenaline increased inward I_ca and outward I_k simultaneously. Both antibody and carbachol could significantly reduce the isoprenaline-stimulated I_Ca but not the isoprenaline-stimulated I_k. The antibody- or carbachol-induced outward K⁺ current and the depressant effects of antibody and carbachol on isoprenaline-stimulated I_ca were partially antagonized by atropine. These results suggest that the anti-M2 muscarinic receptor antibodies display a stimulatory activity similar to muscarinic receptor agonist on the receptor-mediated electrophysiological events.